Fluid ejection devices in inkjet printers provide drop-on-demand ejection of fluid drops. Inkjet printers produce images by ejecting ink drops from ink-filled chambers through nozzles onto a print medium, such as a sheet of paper. The nozzles are typically arranged in one or more arrays, such that properly sequenced ejection of ink drops from the nozzles causes characters or other images to be printed on the print medium as the printhead and the print medium move relative to each other. In a specific example, a thermal inkjet printhead ejects drops from a nozzle by passing electrical current through a heating element to generate heat and vaporize a small portion of the fluid within the ink-filled chamber. In another example, a piezoelectric inkjet printhead uses a piezoelectric material actuator to generate pressure pulses that force ink drops out of a nozzle.
Printhead nozzles are formed in a top layer of the printhead variously referred to as the nozzle plate, nozzle layer, tophat layer, and so on. After a printhead is assembled, the nozzles are sealed to prevent ink from leaking out of the printhead during transportation and storage. One cost effective way of sealing the nozzles is to put nozzle tape over the surface of the nozzle plate. However, nozzle plates are often formed of a relatively soft material such as SU8, or other material such as a polyimide. Therefore the nozzle plate is delicate, and in some areas it can be susceptible to being damaged when the nozzle tape is removed.